[BABEL-5939] Remove custom 'createOrAlter' field in ViewStmt

[R4hul04]

This PR removes a custom field that was added to the core PostgreSQL ViewStmt structure for supporting T-SQL ALTER VIEW operations. Previously, we added a createOrAlter boolean field to the ViewStmt structure to identify T-SQL ALTER VIEW operations. Instead of extending core structures, we'll use the Viewstmt->options list to determine T-SQL ALTER VIEW and CREATE OR ALTER VIEW operations

Corresponding extension PR - babelfish-for-postgresql/babelfish_extensions#3977

PR that introduced createOrAlter field - #545

Issues Resolved

BABEL-5939

Signed off by: Rahul Parande [email protected]

Check List

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[tanscorpio7]

1. Please add [BABEL] prefix to all engine PR titles
2. Interlink the extension and engine, i.e. mention them in each other's description.
3. Add the link to PR that introducued this field.